Location estimation of a wireless communications mobile unit, such as in locating a mobile unit for emergency 911 (E911) calls, is a challenging task for wireless communications. Various location estimation mechanisms have been proposed or implemented for wireless voice communications, which have been the focus of location estimation developments efforts to date.
However, wireless data communications such as text messaging and simple information services through the Short Message Service (SMS) or the Wireless Application Protocol (WAP) has recently experienced dramatic worldwide growth. The proliferation of wireless data communications is likely to continue as 3rd Generation (3G) telephones and systems are developed and implemented, including the Telecommunications Industry Association (TIA) IS-2000 standard defining backward-compatible extension of existing CDMA communications and the proposed International Telecommunication Union (ITU) CDMA2000 1× Evolution for Data Only (1×EV-DO) and CDMA2000 1× Evolution for Data & Voice (1×EV-DV) standards.
There is, therefore, a need in the art for location estimation techniques for mobile stations employing wireless data communications.